#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Literasc, a simple literate programming tool for C, C++, and Turtle.
# Copyright 2012 David Robillard <d@drobilla.net>
#
# Unlike many LP tools, this tool uses normal source code as input, there is no
# tangle/weave and no special file format.  The literate parts of the program
# are written in comments, which are emitted as paragraphs of regular text
# interleaved with code.  Asciidoc is both the comment and output syntax.

import os
import re
import sys


def format_text(text):
    "Format a text (comment) fragment and return it as a marked up string"
    return "\n\n" + re.sub("\n *", "\n", text.strip()) + "\n\n"


def format_code(lang, code):
    if code.strip() == "":
        return code

    head = "[source,%s]" % lang
    sep = "-" * len(head) + "\n"
    return head + "\n" + sep + code.strip("\n") + "\n" + sep


def format_c_source(filename, file):
    output = "=== %s ===\n" % os.path.basename(filename)
    chunk = ""
    prev_c = 0
    in_comment = False
    in_comment_start = False
    n_stars = 0
    code = ""
    for line in file:
        code += line

    # Skip initial license comment
    if code[0:2] == "/*":
        code = code[code.find("*/") + 2 :]

    for c in code:
        if prev_c == "/" and c == "*":
            in_comment_start = True
            n_stars = 1
        elif in_comment_start:
            if c == "*":
                n_stars += 1
            else:
                if n_stars > 1:
                    output += format_code("c", chunk[0 : len(chunk) - 1])
                    chunk = ""
                    in_comment = True
                else:
                    chunk += "*" + c
                in_comment_start = False
        elif in_comment and prev_c == "*" and c == "/":
            if n_stars > 1:
                output += format_text(chunk[0 : len(chunk) - 1])
            else:
                output += format_code(
                    "c", "/* " + chunk[0 : len(chunk) - 1] + "*/"
                )
            in_comment = False
            in_comment_start = False
            chunk = ""
        elif in_comment_start and c == "*":
            n_stars += 1
        else:
            chunk += c
        prev_c = c

    return output + format_code("c", chunk)


def format_ttl_source(filename, file):
    output = "=== %s ===\n" % os.path.basename(filename)

    in_comment = False
    chunk = ""
    for line in file:
        is_comment = line.strip().startswith("#")
        if in_comment:
            if is_comment:
                chunk += line.strip().lstrip("# ") + " \n"
            else:
                output += format_text(chunk)
                in_comment = False
                chunk = line
        else:
            if is_comment:
                output += format_code("turtle", chunk)
                in_comment = True
                chunk = line.strip().lstrip("# ") + " \n"
            else:
                chunk += line

    if in_comment:
        return output + format_text(chunk)
    else:
        return output + format_code("turtle", chunk)


def gen(out, filenames):
    for filename in filenames:
        file = open(filename)
        if not file:
            sys.stderr.write("Failed to open file %s\n" % filename)
            continue

        if filename.endswith(".c") or filename.endswith(".h"):
            out.write(format_c_source(filename, file))
        elif filename.endswith(".ttl") or filename.endswith(".ttl.in"):
            out.write(format_ttl_source(filename, file))
        elif filename.endswith(".txt"):
            for line in file:
                out.write(line)
            out.write("\n")
        else:
            sys.stderr.write(
                "Unknown source format `%s'" % (filename[filename.find(".") :])
            )

        file.close()


if __name__ == "__main__":
    if len(sys.argv) < 2:
        sys.stderr.write("Usage: %s FILENAME...\n" % sys.argv[1])
        sys.exit(1)

    gen(sys.argv[1:])